三峡工程深孔孔口应力分析与配筋设计研究

Stress analysis and reinforcement design on the outlet of deep hole in TGP

泄洪深孔孔口尺寸大(7m×9m),作用水头高(80m),孔口拉应力很大,需配置大量钢筋,且布筋层数多,给施工带来困难。为降低孔口拉应力,减少配筋层数,通过有限元计算方法,对深孔结构基本方案、有压段钢衬方案、横缝灌浆方案等不同结构措施的深入研究,孔口结构受横缝侧水压力作用后,孔口拉应力得以降低,事故门井前孔口配三层36@20的钢筋,门井后孔顶配四层40@20的钢筋,孔底配三层40@20的钢筋,多层钢筋可分散布置在两个浇筑层内。有压段钢衬对限制裂缝开展宽度有利。横缝灌浆对降低孔口拉应力有一定作用,其效果与孔口侧壁刚度、横缝间隙宽度关系很大。

It brings many difficulties to the construction because of the large size(7 m×9 m)of the outlet of deep hole for flood sluicing,high hydraulic pressure(80 m) and high level of the outlet tensile stress, many steel bars must being installed and installed on many lays.By means of the finite element analysis, the deep hole structure plan, steel liner in the pressure section plan and the transverse joint grouting plan are deeply researched in order to decrease the outlet tensile stress and reduces the lays of the steel bars. It is clear that the tensile stress decreased when the outlet are under the lateral hydraulic press of the transverse joint. There are 3 layers of steel bars Φ36@20 in the outlet in front of the well of emergency gate, 4 layers of steel bars Φ40@20 in the top of the outlet behind the well and 3 layers of steel bars Φ40@20 in the bottom of the outlet. These steel bars can be dispersed in 2 concrete lifts. The steel liner in the pressure section can limit the slits. The transverse joint grouting can decrease the outlet tensile stress, and the effect has a relationship to the stiffness of outlet wainscot and the width of transverse joint.